Nanakuli Blackrocks Surf Stats

The graph illustrates the combination of swells directed at Nanakuli Blackrocks through a typical July and is based upon 2976 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind or surf right at the coast so we have chosen the most applicable grid node based on what we know about Nanakuli Blackrocks. In the case of Nanakuli Blackrocks, the best grid node is 40 km away (25 miles). The rose diagram shows the distribution of swell sizes and directions, while the graph at the bottom shows the same thing but lacks direction information. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These were forecast only 67% of the time. Green and yellow illustrate increasing swell sizes and red shows the largest swells, greater than >3m (>10ft). In either graph, the area of any colour is proportional to how frequently that size swell was forecast. The diagram suggests that the most common swell direction, shown by the largest spokes, was SSW, whereas the the most common wind blows from the ENE. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Nanakuli Blackrocks and away from the coast. We group these with the no surf category of the bar chart. To avoid confusion we don't show these in the rose diagram. Because wind determines whether or not waves are surfable at Nanakuli Blackrocks, you can view an alternative image that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. Over an average July, swells large enough to cause good for surfing waves at Nanakuli Blackrocks run for about 33% of the time.

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